Clamp



Nov. 17, 1964 F.. H; WILSON 3315771556 originar. Maren 25,. ww

l mfr/mme :t H401. HIV/50N l 5) @Wwf/4 gm United States Patent O 3,157,556 CLAD/E Paul H. Wson, Maplewood, Minn., assigner to Minneseta Mining and Manufacturing Company, a corporation of Delaware Original application Mar. 25, 1957, Ser. No. 648,073, new Patent No. 3,679,195, dated Dec. 25, 1962. Bivided and this application Feb. Elf-, 1962, Ser. No. 173,196 4 (Iiaims. (Cl. 15d- 583) This invention relates to the assembling of preformed panels into walls and other structural assemblies, as in the erection of pre-fabricated buildings. The invention relates to the novel wall or other assembled structure, and to novel components, methods, and apparatus employed in the assembling thereof.

This application is a division of my application Serial No. 648,073, tiled March 25, 1957, now Patent No. 3,070,- 195.

One type of pre-formed Wall panel which has a number of points of superiority over other known panels is the so-called sandwich type panel consisting of two thin metal plates separated and bonded together by an intervening reinforcing cell-like structure forming the filler of the sandwich. A honeycomb structure of resin-treated paper, the ends of the hexagonal cells being firmly adhesively bonded to the metal panels, is a preferred type of filler. Panels having over-all dimensions of four feet by eight feet and a thickness of three inches are typical. The metal plates forming the outer surfacings ofthe panel may for example, be plates of aluminum alloy having a thickness of .G32 inch, and the maximum distance across each cell of the intervening honeycomb separator may be about one inch, the separator being formed of 7G lb. lrraft paper containing about 18% by weight of phenolic resin. These components are bonded together with a thermosetting phenolic resin adhesive to form a unitary panel of excellent strength and heat-insulating properties.

A number of suggestions have previously been made for connecting these sandwich-type panels in providing wall assemblies. The edges may be butted together and the metal nailed to an interiorly positioned connecting wooden beam or post; but the heads of the nails or other fasteners then remain visible and detract from the appearance of the wall structure. The metal panels may be folded over and clamped together with a fastening strip having a flattened C-shaped cross-section; but the folded vedges do not fit tightly together and the assembly is unstable. Folding the edges outwardly makes possible the direct fastening together of the extended flanges, eg., with bolts, screws, or clamps; but these are unsightly and must be covered.

Another proposed system involves forming an inwardly facing double right-angle fold at the edges of each metal Y plate, to provide reinforced flat edge surfaces which may be abutted against thecorresponding edge surfaces of adjacent panels and sealed in place with metal C-strips or more complicated means. Obviously these internal edges are dimcultly accessible, and elaborate sealing means have been evolved in an effort to operate successfully within the space provided. One such sealing means requires a metal connection between opposing face-plates and thus provides an undesired heat-conductive path between inner and outer wall surfaces. The dat edges are not truly planar but have ripplerd or uneven surfaces which do not lit tgether to form a liquid-tight seal, and the assembly tends to loosen under application of variable pressures or vibration.

The present invention provides means for overcoming these and other prior art deficiencies and results in a fluidtight, dust-proof, strong, pressure-resistant and vibrationresistant, smooth and esthetically acceptable wall structure of bonded pre-formed sandwich type panels. The invention provides a new type of panel edge structure which is adapted for immediate bonding. Means for effecting the desired strong and resistant bond between panel edges in the assembling of a wall or other building element are also provided. Elongate clamping apparatus for applying the required heat and pressure at the panel edges within the wall section in thus bonding together adjoining wall components is included and forms the Subject of the present application.

The invention will now be further described and illustrated in connection with the accompanying drawings, in which:

FIGURE 1 is a partial elevation representing the bonded panel structure;

FIGURE 2 is a View in cross-section of a typical clamp member in position for, and just prior to bonding together of adjacent pre-fabricated panels; and

FIC-URE 3 is a view in elevation and partly in section taken along the line 3 3 of FIGURE 2.

The segment illustrated in FIGURE 1 consists of two pre-fabricated panels lil and 11 permanently adherently sealed and bonded together along a joint area 12.

The panels iti and 1i are illustrated in FIGURE 2 as consisting of sheet aluminum facing elements 26, 21, 22 and 23, the elements of each panel being separated and held in position as shown in connection with panel 10, by an intervening honeycomb structure of resin treated paper 24. For descriptive purposes the edges of the hexagonal honeycomb cells are here illustrated; however these cells are normally aligned perpendicularly to the panels 2b, 21 rather than parallel thereto. The abutting edges of the metal facing elements are doubly folded at right angles to provide reinforced facing edges 25, 26, 27 and 28. A strip of temporarily heat-softening thermosetting adhesive film 29 is applied to face 25 and a similar strip 36 to face 26. The two panels i@ and 11 are then placed in position as indicated, and the opened clamp 31 is slid between the abutting facing elements and over the abutting folded edges, all as indicated in FiGURE 2. Clearances, while small, are adequate to permit the clamp to be slid the full distance of the panel edge, i.e., up to a total of at least eight feet.

The clamp 31 comprises two frame members 32 and 33, in the general form of shallow U-beams or channel-irons having cooperatively opposing flange edges, held together at periodic intervals by pressure imparting means here indicated as comprising a shaft 34 passing through the web of beam 33 and connected to a piston 35 fitting Within a cylinder 35 in the web of beam 32.

The shaft 34- is held to the member 33 by external fastening means here shown as nut 37 and washer 3S, and by internal expansion spring 39. A sealing ring 4G is provided in a suitable channel in the shaft 34, forming a seal `against the walls of opening 41 in the base of the cylinder 36. VA similar sealing ring 42 is provided on the periphery of the piston 35, forming a seal against the interior of the surface of the cylinder 36.

The interior of the cylinder is connected through tube 43 to a supply tube 44 which in turn is connected to source of hydraulic pressure. Y f

The ilanges of the U-beam 33 are shown in FIGURE 2 to be tted with heat conductive shoemembers 45, 45, and to be provided with channels underlying `said shoe members and containing heater elements 47, 48. Similar structure may be employed on the anges of the U-beam member 32 if desired.

In operation, the opened clamp member 31 is slid into position within the previously prepared joint area. rThe clamp is of suiicient length to tit over the entire joint area of the two panels 10 and 11, and the number of pressure units is suicient to provide for uniform presjsurealong the entire edge areas. The heater elements 47, 48 are connected to a source of current, and the supply tube 44 is attached to a hydraulic pump system,

not shown. VApplication of hydraulic pressure from the pump system causes the clamp to close and forces the folded edges of the panels together against the intervening strips of adhesive film, as is apparent by reference to FIG- URE 1 Vof the drawing. The Yheating effect provided through the elements @7,V 43, first causes the film to soften and, under the pressure imparted by the clamp, to idowinto fullcontact with all surfaces, and then to cure to the final tough and adherent stage. As soon as the cure is completed, the current is turned off in the heat elements and the hydraulic pressure is released. The spring 39 then forces the U-beams 32 and 33 apart,V and the clamp may be slid from the assembly.

' Various heat-setting adhesives in film form are known which are capable of forming the required high strength adherent bond to aluminum. One preferred film comprises a rubbery butadiene-acrylonitrile polymer, an oilsoluble heat-advancing phenol-aldehyde resin, land a small proportion of a Vrapidly reacting heat-activated curing agent such as 2,6-dibromomethyl-4-me-thylphenol. Typical adhesives of this character are described in Palmquist yet al. Patent No. 2,726,222.

The adhesive film in narrow strip forni is first lightly adhered to one ofthe surfaces to be bonded, as indicated in FGURE 2. The film may be spot-welded to the V,clean surface, for example by light pressure with :a heated v .A soldering-iron or'the like at intervals. A preferred procedure involves wiping the metal surface with a suitable volatile solvent, eg., methyl isobutyl ketone, and then pressing the film against the still damp surface. The solvent removes any oil deposits remaining on the metal, activates the surface of the film to a temporarily tacky state, and thereby provides continuous adherent contact l between film, and metal. In FIGURE 2 the film strips 29,

`are shown adhered to the reinforced flat' edges 25, 26 respectively. Obviously the film could equally Well be adhered to the opposing faces 27, 28 or to one face of' each panel, providing the heating'elements are approf priately disposed in the clamp. Since the film is separately prepared,Y it is of uniform thickness and smooth-surfaced, so'that well-fitting joints become possible.Y The panels are conveniently supplied with the bonding strips in place on appropriate surfaces and protected with a Y removable liner, eg., of treated fabric or paper.

'Y reactive bonding film is available.

Application of hydraulic pressure to the piston and cylinder members of the clamp 31 forces the edges of the .panels together. The heat supplied by the cables 47, 4S vcauses the bonding strips to temporarily soften and become firmly 'adherently attached to the metal, and `then *to rapidly set up or cure to an effectively,non-thermoplasticor heat-resistant and extremely strong state. Thereafter the heating maybe discontinued and the clamp relaXed and removed.

' i With the adhesive film formulation given hereinabove,

the .cure is so rapid that but little heating of the Yclamp occurs KVWith llessrapid cures and consequent longer currecycles it is desirable to employ heaterv elements beneath or'at the'surface of bothl of the opposing clamp members, and` alsoyto-provide insulating means "for reducing the flow of heatiinto other parts of the clamp. y' For the Vlatter purpose, ceramic or asbestos inserts beneath the heater elements are'contemplated. Ceramic i shoes may be placed over the heat-conductive metal edges ofVU-beam 32,' or heat-insulating annular connector elements maybe used to isolate cylinder 36 from beam 32 ordinarilynot required whereV suiiciently rapidly heat- Anexemplary clampV memberY useful in .joining sand- Y jand rod 34 from beam l3.3. However these devices are Awich .typepan'els as herein described is Yeight feet in length and has va piston and cylinder4 assembly every four inchesalong its length; f Thekclampis capable ofY providing pressures of the order of 40G lbs. per sq. in. when operating on panel faces having a width of approximately onehalf inch and at a hydraulic pump pressure of about 150 lbs. per sq. in. At these pressures the temporary heatsoftened bonding film flows suiiiciently to make adequate adhesive contact with the opposing metal surfaces and to fill all low areas in the panel edges; and any unduly deformed or imperfect metal edges are themselves straightened and conformed.

When the bonding film has been heat-cured under con-l nections between the metal facing sheets. The extremely narrow seam or joint area may be smoothed o5 to remove any extruded bonding material and is then not displeasing in appearance, andfmay be further concealed by painting. j

What l claim is: K l Y l. An elongate compact clamp member fitting between, and adapted for use in adherently bonding together, two structural panelmembers in the assembling of a bonded multiple-panel wall structure as herein described and Y i wherein each panel member comprises two parallel thin sheet metal surfaceor skin elements separated and supported by an interposed insulative supporting structure,

the two elements being oppositely doubly edge folded to provide Yextended narrow flat reinforced edges for cooperatively connectingwith the corresponding edges of an 'adjacent panel, said Vedges being directed toward the in- Iterior of the panel and being separated from each other; said clamp member comprising first and second elongateV v shallowV U-beams having continuous opposing flat edge Y portions forming'two pairs of jaw elements; and, compactly disposed vbetween said beams, multiple pressure-applying means for forcing together the opposing jaw elements to impart substantiallyuniform high unit pressure across cooperating sets of panel redges therebetween, and means for separating the opposing jaw elementsV on release of said'pressure-applying means.

2. An elongate compact clamp member fitting between, and adapted Vfor use in adherently bonding together, two structuralj panel members in the-,assembling y of a bonded multiple-panel wall structure as herein de-'J scribed and wherein each panel member comprises two f parallelthin sheet; metal surface or skin elements separated and'supported by ain-interposed insulative supporting structure, Ithe two elements being oppositely doubly edge folded to provide extended narrow dat reinforced edges for cooperatively connectingrwith the correspond-` ing edges of an adjacent panel, said edgesY being directedtoward the interior of the panel and being separated from each other; said clamp-member comprising first Vand s ecff Q ond elongate shallow U-beams having'continu'ous opr'losyV ing fiat edge portions forming twor pairs of jaw elements; and, compactly disposed between said beams, multipleV` 'hydraulic pressure means for forcing togetherV the oppose?V ing jaw elements to impart substantially uniform high unit` Vpressure acrosscooperating sets of panel'edgestherebetween, means for supplying heat at the surface of at least one of each pair of-jaw elements, andfmeans for .separat- Y i ing the opposing jaw elementson release bfsaid pressure means.

Y 3. An elongate compact clamp'member fitting betvifee'n',VV 'Y and adapted for use in adherently. bonding tgetherftwo Y, Vstructural panelmembers inthe assembling` of a bonded Ymultiple-panel wall structure asherein Vdescribed andY il .Y

wherein each panel member comprises two parallel thin sheet metal surface or skin elements separated and supported by an interposed insulative supporting structure, the two elements being oppositely doubly edge folded to provide extended narrow at reinforced edges for cooperatively connecting with the corresponding edges of an adjacent panel, said edges being directed toward the interior of the panel and being separated from each other by a thin strip of temporarily thermoplastic rapidly heatcurable adhesive lm; said clamp member comprising first and second heat-conductive metallic frame members in the form of elongate shallow U-beams or channelirons positioned with the ange edges of said first member opposing the ange edges of said second member to provide two pairs of jaw elements; heater means associated with at least one jaw element of each of said pairs for supplying heat at the corresponding of said ange edges; insulating means for minimizing heat ilow within said frame members toward web portions thereof; and compactly disposed between said frame members, multiple hydraulic pressure applying means uniformly spaced along the Webs of said frame members for forcing opposing jaw elements of each pair towards each other with substantially uniform high unit pressure, and compression spring means for separating the opposing jaw elements on release of hydraulic pressure.

4. A clamp assembly as herein described and comprising: a rst and a second narrow shallow elongate channel-iron, the open faces of the two facing each other with the ange edges of the irst opposing the flange edges of the second to provide two pairs of elongate opposing jaw elements and a central channel therebetween; a series of uniformly closely spaced open-ended shallow cylinders disposed along and attached to the web of said iirst channel-iron, each of said cylinders being provided with a central opening through the closed end thereof and communicating with said channel; a piston in each said cylinder; a connecting-rod for each said piston, slidably passing through the lcentral opening in the closed end of the said cylinder and across said channel and attached to the web of said second channel-iron; a coiled compression spring surrounding each said connecting-rod for urging said channel-irons apar-t to Ithe extent permitted by said rods; and a vent to the interior of each said cylinder for communicating with a source of hydraulic pressure available within said channel in the applying of hydraulic pressure to said pistons within said cylinders whereby to urge said opposing jaws strongly and uniformly toward each other.

References Cited in the le of this patent UNITED STATES PATENTS 1,890,114 Fulton Dec. 6, 1932 2,644,194 Fill July 7, 1953 2,651,350 Casey et al. Sept. 8, 1953 

1. AN ELONGATE COMPACT CLAMP MEMBER FITTING BETWEEN, AND ADAPTED FOR USE IN ADHERENTLY BONDING TOGETHER, TWO STRUCTURAL PANEL MEMBERS IN THE ASSEMBLING OF A BONDED MULTIPLE-PANEL WALL STRUCTURE AS HEREIN DESCRIBED AND WHEREIN EACH PANEL MEMBER COMPRISES TWO PARALLEL THIN SHEET METAL SURFACE OR SKIN ELEMENTS SEPARATED AND SUPPORTED BY AN INTERPOSED INSULATIVE SUPPORTING STRUCTURE, THE TWO ELEMENTS BEING OPPOSITELY DOUBLY EDGED FOLDED TO PROVIDE EXTENDED NARROW FLAT REINFORCED EDGES FOR COOPERATIVELY CONNECTING WITH THE CORRESPONDING EDGES OF AN ADJACENT PANEL, SAID EDGES BEING DIRECTED TOWARD THE INTERIOR OF THE PANEL AND BEING SEPARATED FROM EACH OTHER SAID CLAMP MEMBER COMPRISING FIRST AND SECOND ELONGATE SHALLOW U-BEAMS HAVING CONTINUOUS OPPOSING FLAT EDGE PORTIONS FORMING TWO PAIRS OF JAW ELEMENTS; AND, COM- 